<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<style>
.box{
	width:400px;
	height:400px;
	margin:50px auto; 
	transition:5s linear;
}
.box div{
	width:180px;
	height:180px;
	margin:10px;
	border:1px solid #000; 
	box-sizing:border-box;
	float:left;
	background:pink;
}
.box div:nth-child(1),.box div:nth-child(4){ 
	border-radius:0 60%;
}
.box div:nth-child(2),.box div:nth-child(3){ 
	border-radius:60% 0;
}
.box:hover{
	transform:rotate(720deg);
}
</style>
</head>
<body>
<div class="box">
	<div></div>
    <div></div>
    <div></div>
    <div></div>
</div>
</body>
</html>
